What is different about humans from other primates that make them stand out? Even though our brains are likewise, it looks like they behave differently to an assorted stimulus. Latest research advises that human brain “listen” for musical pitch, a liking that scientists have not found in monkeys.
Humans and other primates are very much the same in various ways, so what is different in humans, precisely? Scientists have been looking for a way to answer this question since decades with contrasting degrees of success.
The studies conducted before have seen that brains of humans and nonhuman primates process visual information in a similar way. Yet, researchers are still unsure as to if there are any contrasts in how we and our primate “cousins” function different types of sounds.
This is exactly the area that scientists from the the Massachusetts Institute of Technology in Cambridge, MA, and the Laboratory of Sensorimotor Research, of the National Eye Institute of the National Institutes of Health in Bethesda, MD, lately planned to research.
In their research which is published in Nature Neuroscience, the researchers describe that the “visual cortex is the same between humans and macaque monkeys, but very little information is known about audition” contrasts in two species.
The research team then started to compare how the brains of humans and those of rhesus macaques behaved to auditory stimuli, especially ones that we generally associate with humans, known as harmonic tones that characterize music and speech.
“Speech and music consist of harmonic frequency components which are recognized to have ‘pitch, “authors describe in their paper. “Humans have cortical regions with a powerful reply for harmonic tones versus noise, “But are it correct for nonhuman primates?”
“We discovered that a particular area of our brains have a powerful preference for sounds with pitch than macaque monkey brains,” describes senior author Bevil Conway, Ph.D., about the present research results.
“The outcomes increase the likeliness that these sounds, which are implanted in speech and music, may have structured the basic organization of the human brain.” Says Bevil Conway, Ph. D.
Humans are reactive to ‘pitch’
For the research, the researchers worked with three rhesus macaques and four human individuals, playing them harmonic tones and noise that consisted of four contrasting frequency ranges.
Using functional MRI images, the team calculated the monkey and human brain reactions to the different sounds and frequency ranges.
The first investigation of functional MRI scans appeared as advising that there was not much of a difference in brain reactions between humans and monkeys – both the human individuals and the macaques displayed triggering of the similar parts of the auditory cortexes.
But later when the researchers evaluated the scans deeply, they realized that human brains looked as more sensitive to “pitch” in harmonic tones than the brains of rhesus macaques, which appeared not to differentiate between harmonic tones and regular noise.
“We discovered that human and monkey brains had alike reactions to sounds in any given frequency range. It’s when we added tonal structure to the sounds that few of these alike areas of the human brain became more responsive,” describes Conway.
“These outcomes advise the macaque monkey may encounter music and other sounds differently,” he further adds, including that “in difference, the macaque’s encounter of the visual world is likely same to our own.”
“It makes me think what type of sounds our evolutionary ancestors encountered,” Conway thinks.
They also revealed the macaques to sounds with more natural harmonies – such as recordings of macaque calls – the outcomes were still the same, backing up the idea that human brains are more sensitive to “pitch”.
“The present results may also provide explanation for why it has been so difficult for scientists to teach monkeys to perform auditory duties that humans feel as quite effortless”, records Conway.